The removal of unwanted and/or life threatening biological material from interior portions of bodily cavities, such as organs, vessels, articular joints and structures, sinuses, and various bodily lumens, is a very common procedure in various medical specialties and disciplines, such as pulmonology, cardiology, urology, gynecology, gastro-enterology, neurology, otolaryngology, orthopedics, and general surgery. Recently, balloon catheters have been employed to release sinus congestion. Accordingly, various instruments and methods have been employed to perform these procedures, which are generally well known in the art.
The nasal cavity (or nasal fossa) is a large air filled space above and behind the nose in the middle of the face. The floor of the nasal cavity, which forms the roof of the mouth, is made up by the bones of the hard palate: the horizontal plate of the palatine bone posteriorly and the palatine process of the maxilla anteriorly. To the front of the nasal cavity is the nose, while the back blends, via the choanae, into the nasopharynx.
The paranasal sinuses are hollow cavities in the skull connected by small openings, known as ostia, to the nasal canal. Each ostium between a paranasal sinus and the nasal cavity is formed by bone covered by a layer of mucosal tissue. Normally, air passes into and out of the paranasal sinuses through the ostia and into the nasal canal.
The paranasal sinuses include the maxillary sinuses, the frontal sinuses, the ethmoid sinuses, and the sphenoid sinuses. The maxillary sinuses are also called the maxillary antra and are the largest of the paranasal sinuses. They are located under the eyes, in the maxillary bones. The frontal sinuses are superior to the eyes, in the frontal bone, which forms the hard part of the forehead. The ethmoid sinuses are formed from several discrete air cells within the ethmoid bone between the nose and the eyes. The sphenoid sinuses are in the sphenoid bone at the center of the skull base under the pituitary gland. Sinusitis is an inflammation of the sinus lining commonly caused by bacterial, viral and/or microbial infections; as well as, structural issues such as ostial blockage. Symptoms include nasal congestion, facial discomfort, nasal discharge, headache, and fatigue. Sinusitis can be considered acute (last 4 weeks or less) or chronic (12 weeks or longer).
Sinusitis affects 29.3 million people each year, making it one of the most common health problems in the U.S. according to the U.S. Department of Health and Human Services, Centers for Disease Control and Prevention National Center for Health Statistics, Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2009 (2010). It is responsible for great healthcare expenditures and a significant loss of workplace activity.
Another common ailment affecting the nose and paranasal sinuses is nasal polyps. Nasal polyps are benign masses that grow from the lining of the nose or paranasal sinuses. Nasal polyps often result from chronic allergic rhinitis or other chronic inflammation of the nasal mucosa. Nasal polyps are also common in children who suffer from cystic fibrosis. In cases where nasal polyps develop to a point where they can obstruct normal drainage from the paranasal sinuses, they can cause sinusitis.
Various drugs have been used to treat sinusitis, including antibiotics and corticosteroid sprays. However, with the use of intranasal sprays, most of the spray does not actually enter the affected sinuses. Accordingly, introduction of drugs directly into the sinuses has been proposed. For instance, U.S. Pat. No. 7,361,168 to Makower et al. discloses implantable devices that may be positioned within a naturally occurring or man-made cavity or passageway in a nostril, nasal cavity, sinus, etc. via balloon catheters.
Functional Endoscopic Sinus Surgery (FESS) is the most common surgical procedure for clearing blocked sinuses. However, the procedure involves removing bone and tissue, which can lead to post-operative pain, scarring and bleeding. The use of balloon catheters in sinus surgery can minimize or eliminate many of these drawbacks.
One method involves creating a new opening from a sinus into the nose to dilate a sinus ostium or duct, or to excise a sinus. U.S. Pat. No. 7,854,744 to Becker discloses methods of performing balloon catheter astronomy of the maxillary ostium, middle meatal maxillary ostium, and inferior meatal ostium and a method of performing ethmoidectomy of the anterior ethmoid sinus, posterior ethmoid sinus, and sinusotomy of the frontal sinus. The methods generally involve pushing a balloon catheter through the ostia into the desired sinus cavity, inflating the balloon to 9 bar for 20 seconds, and deflating the balloon. This may be repeated. After final deflation, the catheter is removed from the enlarged ostium. The catheters employed by Becker utilize stainless steel catheters with radia of 0.13 inches, length of 4 to 10 inches, and wall thickness of at least 0.035 inches. The catheter tip contains a curved distal tip with an angle of 70° to 180°. The distal tip contains a balloon formed of polyethylene terephthalate with a length of 4 mm to 30 mm and working inflated diameter of 2 mm to 15 mm. The balloon has a distal neck and distal tapered region that is adhered to the distal tip of the catheter using an adhesive, such as cyanoacrylate.
In at least some procedures wherein it is desired to position a balloon catheter in the ostium of a paranasal sinus, it is necessary to advance the balloon catheter through complicated or tortuous anatomy in order to properly position the balloon catheter within the desired sinus ostium. Also, there is a degree of individual variation in the intranasal and paranasal anatomy of human beings, thus making it difficult to use the stiff-shaft preshaped balloon catheters of Becker for use in all individuals. The Becker patent describes the necessity of having available a set of balloon catheters, each having a particular fixed angle so that the physician can select the appropriate catheter for the patient's anatomy.
Accordingly, a series U.S. Patents to Chang et al. (e.g. U.S. Pat. No. 7,727,226) disclose methods utilizing flexible balloon catheter devices for use in ENT procedures. Exemplary methods for improving drainage from a paranasal sinus that has a natural ostium comprise inserting a guidewire to a position near the ostium, using the guide to advance a balloon catheter within the ostium and using the balloon to dilate the natural ostium. A sizing balloon situated around the dilating balloon may be inflated using an imageable inflating medium, such as saline with radioopaque contrast agent or carbon dioxide gas. The distal region of the sizing balloon is imaged to enable the operator to estimate the size of the anatomical opening or the diameter of the narrowest region in a tubular anatomical region. Chang et al. also provide methods for treating mucocysts or other flowable substance containing structures located in the sinus by penetrating the structure, compressing the structure with, for example, the balloon of a balloon catheter to force the contents out of the opening formed by the penetrator, advancing the penetrator into the sinus and opening in the cyst, and positioning the balloon in the sinus using the balloon to force the contents out of the opening formed by the penetrator.
A common risk, however, with the above described methods and apparatus is the possibility of under or over-inflation of the balloon portion of the catheter. In the case of under-inflation, the effect of the catheterization on the ostium may be insufficient and therefore require additional treatments, adding to procedure times and increasing the risk of complications. In the case of over-inflation, the balloon catheter can fracture the ostium, leading to restenosis.
Imaging modalities, such as those used with a sizing balloon, cannot assess information regarding pressure or volume of inflated balloons. Variation in constriction responses associated with the nature of an obstruction highlight the importance of control over dilation set-points such as the rate of dilation, pressure, volume and the diameter of the inflated balloon. Many patient maladies are simply not remedied by these procedures because the methods are not efficient, safe, and reproducible, and/or the instruments employed lack the appropriate physiological measurement and/or feedback necessary to ensure the safety, efficacy, and reproducibility of the procedure.
Further, simple pressure control means, such as those described in US 2003/0105483 to Hudson et al., are not optimal because they only involve controlling pressure to a pre-set level through valve caps. The pre-set can prevent extreme over-inflation, but requires the user to approximate a pre-set value and does not allow for real time monitoring and feedback as the balloon is within a nasal or paranasal lumen. The pre-set also does not account for under-inflation when the diameter of an ostium is larger than anticipated.
Hence, there is a significant need for systems and methods for deforming the sinus ostia that are capable of accurately and directly determining in vivo the size and optionally the compliance of areas of the nose, nasal cavities, and paranasal sinuses, such as the ostia. Such systems and methods should be relatively simple to accommodate a single-use strategy.